Saliva and peripheral blood samples from 20 healthy adults were examined for the presence of human herpesvirus-6 (HHV-6) DNA sequences using the polymerase chain reaction. Eighteen out of 20 whole saliva samples contained detectable HHV-6 genomes. The majority of peripheral blood samples were also positive; however, the results suggest that only a rare cell in the peripheral blood is infected. Serological studies did not reveal any correlation between HHV-6 antibody titre and the ability to detect HHV-6 DNA. The data indicate that HHV-6 genomes persist in the peripheral blood and oropharynx or salivary glands of most healthy individuals following primary infection.